Hi all.   I've been learning for a year.  I waited too long to change my guitar strings.  The note D (10th fret, high E string) was producing a twang sound.  I changed the strings but the same thing is happening.  No matter where or how hard I place a finger this note is never clear.  Now I'm starting to have the same problem with note A on 10th fret B string.  Thank you in advance for any suggestions.